How to Grow Dahlia

Start Dahlia seeds indoors 6 weeks before your last frost date, then transplant outdoors 1 weeks after the last frost. Use the search on this page to find exact dates for your ZIP code or city.

Dahlia typically blooms in about 90 days from planting. Exact timing varies by variety, soil conditions, and local climate.

Dahlia should be started indoors 6 weeks before the last frost date. This gives seedlings time to establish before being transplanted outside after frost danger has passed.

Dahlia requires full sun (6-8 hours) to thrive.

Space Dahlia plants 18 inches apart to allow adequate airflow and root development.

Dahlia has regular (1-2 inches/week) water needs. Consistent moisture is important especially during germination and early growth.

Yes — seed saving difficulty for Dahlia is rated moderate. Allow seed pods (behind the flower) to dry on the plant in fall. Remove dried seed pods, extract flat seeds, dry 1 week in an open envelope.

Properly dried and stored Dahlia seeds remain viable for up to 2 years. Store in a cool, dark, dry location in an airtight container with a silica gel packet for best results.

Many commonly sold Dahlia varieties are F1 hybrids, meaning seeds saved from them will not grow true to the parent plant. For reliable seed saving, look specifically for open-pollinated or heirloom varieties.